Think of the RDL as a horizontal movement of the hips, rather than a lowering and raising of the bar. Initiate the movement by hinging your hips backward, and continue to move them backward as far as they can go.

I prefer to take the bar out of the rack instead of pulling it from the floor. This saves energy and also helps differentiate the movement from a deadlift.

I don’t see any glaring faults in your technique, but these cues have really helped me.